Understanding Optics: Paraxial Magnification & Snell's Law Simplified

  • Thread starter Thread starter jlmac2001
  • Start date Start date
  • Tags Tags
    Optics
AI Thread Summary
Understanding the problem of paraxial magnification involves recognizing the small-angle approximation in optics, where angles are approximated by their tangents. The magnification produced by a single spherical interface between two media is described by the formula Mt = -n1s1/n2s0, indicating that the image is inverted. The variables s1 and s0 represent the distances of the object and image from the lens, respectively. To derive this formula, one can start with the basic magnification equation and incorporate Snell's Law to relate the distances to the refractive indices of the media. Mastery of these concepts is essential for solving optical problems effectively.
jlmac2001
Messages
75
Reaction score
0
I don't understand how to do the following problem. I don't even know where to start.

Problem: Show that, in the paraxial domain, the magnification produced by a single spherical interface between two continious media given by Mt=-n1s1/n2s0. Use the small-angle approximation for Snell's Law and approximate the angles by their tangents.
 
Physics news on Phys.org


Understanding optics and concepts like paraxial magnification and Snell's Law can be challenging, but with some practice and knowledge of the basic principles, you will be able to solve problems like this one.

To start, let's break down the problem into smaller parts. First, we need to understand what is meant by "paraxial domain." In optics, the paraxial domain refers to a small angle approximation, where the angles involved are small enough that we can use the tangent of the angle instead of the angle itself.

Next, we need to understand what is meant by "magnification produced by a single spherical interface between two continuous media." This refers to the change in size of an object when it passes through a curved surface, such as a lens. In this case, we are looking at a single spherical lens that separates two continuous media, with different refractive indices (n1 and n2).

The formula given, Mt=-n1s1/n2s0, represents the paraxial magnification produced by this spherical interface. The letters "s1" and "s0" represent the distances of the object and image from the lens, respectively. The negative sign indicates that the image is inverted compared to the object.

To solve this problem, we will use the small-angle approximation for Snell's Law, which states that sin θ ≈ θ for small angles. This allows us to use the tangent of the angles instead of the angles themselves.

Now, let's look at the problem step by step. We need to show that Mt=-n1s1/n2s0. We know that Mt represents the magnification, so let's start by finding the expression for it.

To do this, we can use the basic formula for magnification, which is given by M = -s'/s, where s' is the distance of the image from the lens and s is the distance of the object from the lens. Since we are dealing with a spherical interface, we can use the radius of curvature of the lens (R) to express s' and s.

s' = R - s0 and s = R - s1

Substituting these values into the magnification formula, we get:

Mt = -(R-s0)/(R-s1)

Next, we need to use Snell's Law to express the distances s0 and s1 in terms of the refractive indices (n1 and n2)
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top